What I suspect is that tech companies have many more workers than needed, because most software simply doesn’t need many people to build and maintain. I remember massive tech companies running on teams of <100 people, and even today, I hear of many critical departments with only around a dozen or less.
Google search, Github, AWS, Outlook, Facebook, Uber, IntelliJ. These are software behemoths, but at their core they’re rather simple, and a single developer could make an MVP of any in a few weeks, and with adequate testers and resources, something scalable and stable that could be used by professionals in a few months. And that’s creating it from scratch (well, existing libraries), though maintaining everything maybe doesn’t require much less, it surely doesn’t require more. I understand the big products have more, at least name recognition, and I understand that a big product needs more than programmers (asset creation, marketing, QA, tech support, accounting, etc.) But the software development side isn’t very big, especially if you already have the software.